U.S. patent application number 13/697203 was filed with the patent office on 2013-02-28 for device for compressing and drying gas.
The applicant listed for this patent is Christophe Briers, Stijn Jozef Rita Johanna Janssens, Uwe Pahner. Invention is credited to Christophe Briers, Stijn Jozef Rita Johanna Janssens, Uwe Pahner.
Application Number | 20130047661 13/697203 |
Document ID | / |
Family ID | 43587495 |
Filed Date | 2013-02-28 |
United States Patent
Application |
20130047661 |
Kind Code |
A1 |
Janssens; Stijn Jozef Rita Johanna
; et al. |
February 28, 2013 |
DEVICE FOR COMPRESSING AND DRYING GAS
Abstract
Device for compressing and drying gas includes a multistage
compressor with a low pressure stage, a high pressure stage, and a
pressure pipe; and an adsorption dryer with a drying zone and a
regeneration zone. An intercooler is located between the low
pressure stage and high pressure stage, and the device includes a
heat exchanger with a main compartment with an inlet part and an
outlet part for a first primary fluid. The ends of the tubes of the
heat exchanger are connected to a separate inlet compartment and
outlet compartment for each series of tubes. A first series of
tubes forms a cooling circuit of the intercooler in order to heat
up gas from the high pressure stage for the regeneration of the
adsorption dryer.
Inventors: |
Janssens; Stijn Jozef Rita
Johanna; (denderleeuw, BE) ; Pahner; Uwe;
(Leuven, BE) ; Briers; Christophe; (Hasselt,
BE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Janssens; Stijn Jozef Rita Johanna
Pahner; Uwe
Briers; Christophe |
denderleeuw
Leuven
Hasselt |
|
BE
BE
BE |
|
|
Family ID: |
43587495 |
Appl. No.: |
13/697203 |
Filed: |
May 11, 2011 |
PCT Filed: |
May 11, 2011 |
PCT NO: |
PCT/BE2011/000028 |
371 Date: |
November 9, 2012 |
Current U.S.
Class: |
62/474 |
Current CPC
Class: |
B01D 53/06 20130101;
B01D 53/261 20130101; F28D 7/0083 20130101; F28D 7/06 20130101;
F28F 9/0241 20130101; F28D 7/16 20130101; F28D 7/1607 20130101;
F04F 1/18 20130101; F28F 9/22 20130101; B01D 2259/4009 20130101;
F28D 7/0091 20130101; B01D 2259/4005 20130101 |
Class at
Publication: |
62/474 |
International
Class: |
F25B 43/00 20060101
F25B043/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 11, 2010 |
BE |
2010/0284 |
Claims
1.-14. (canceled)
15. Device for compressing and drying gas, comprising: a multistage
compressor having a low pressure stage, a high pressure stage with
a pressure pipe and an adsorption dryer with a drying zone and a
regeneration zone; an intercooler located between the low pressure
stage and high pressure stage, a heat exchanger connected to an
inlet part by the pressure pipe, the heat exchanger including a
housing with a number of compartments, including a main compartment
with said inlet part and outlet part for a first primary fluid that
is guided in the main compartment over or around tubes that extend
through the main compartment; at least two series of tubes that
extend through the main compartment, and which are each configured
to guide a secondary or tertiary fluid through the main compartment
to exchange heat with the primary fluid; the ends of the tubes
being connected respectively to a separate inlet compartment and
outlet compartment for each series of tubes; and a first of said
series of tubes forming a cooling circuit of the intercooler
arranged to heat gas from the high pressure stage for the
regeneration of the adsorption dryer.
16. The device according to claim 15, wherein the main compartment
comprises a number of inlet and outlet parts for a number of
primary fluids.
17. The device according to claim 15, wherein the main compartment
is bounded by two end plates and on either side of the main
compartment a cover forms two side compartments between each
respective end plate and a cover opposite it.
18. The device according to claim 17, wherein the tubes are
fastened in one of the end plates.
19. The device according to claim 17, wherein the side compartments
include the inlet and outlet compartments.
20. The device according to claim 19, wherein the side compartments
are subdivided into two or more sub-compartments and the respective
sub-compartments are connected on either side of the main
compartment by the series of tubes such that at least two separate
circuits for at least the respective secondary and tertiary fluid
are formed.
21. The device according to claim 15, wherein the main compartment
includes baffles, for the primary fluid.
22. The device according to claim 15, wherein the heat exchanger
includes two or more extra fluids and the respective side
compartments are subdivided on either side of the main compartment
by partitions in the inlet and outlet compartments, including a
first inlet and outlet compartment that connects to a first group
of tubes and guides a secondary fluid and a second inlet and outlet
compartment connecting a second group of tubes guiding a tertiary
fluid.
23. The device according to claim 22, wherein a seal is provided
between the partitions and end plates.
24. The device according to claim 22, wherein a space is provided
between the first group and second group of tubes.
25. The device according to claim 22, wherein the tubes of the
first and second group are distributed over a sector of a
circle.
26. The device according to claim 22, wherein the tubes are
distributed in a concentric arrangement, so that a first group of
tubes is located within a circle and a second group of tubes is
located in a ring around said circle.
27. The device according to claim 15, wherein the inlet and outlet
part of the heat exchanger are located on a side of the shell that
borders the main compartment.
14. The device according to claim 15, wherein the first inlet and
the first outlet compartment are located on an opposite side of the
heat exchanger, while the second inlet and outlet compartment are
located on the same side of the heat exchanger.
Description
[0001] The present invention relates to a device for compressing
and drying gas.
[0002] Tube heat exchangers are already known that consist of a
housing in which one or more tubes extend in the longitudinal
direction between a first inlet and outlet part for a first fluid,
and a second inlet and outlet part for a second fluid, whereby the
first fluid flows through the tubes and the second fluid flows
around the tubes, whereby heat is transferred between the two
fluids.
[0003] In the known heat exchangers the space in the housing
between the second inlet and outlet part can have baffles that
guide the flow of the second fluid in a zigzag pattern, for
example.
[0004] In so doing the second fluid cannot flow directly from the
second inlet part to the second outlet part and the heat transfer
is improved.
[0005] Furthermore, it is known that the compression of a gas is
coupled with the generation of an enormous amount of heat.
[0006] There are also already heat exchangers in which a fraction
of the compressed gas is guided through a primary circuit of a heat
exchanger and thus gives off its heat to another gas or liquid
flowing through a secondary circuit of the heat exchanger, whereby
this second fluid heats up.
[0007] Devices have been known for a long time for compressing and
drying gas, whereby these devices are composed of a compressor
device and a drying device, and whereby the drying device is formed
by a drying zone with a desiccant and a regeneration zone.
[0008] There are also devices in which the heat generated by the
compression of the gas is recovered.
[0009] Thus this heat can be used, for example, to heat the gas
flow that is guided through the regeneration zone, such that the
total energy consumption of the compressor installation can be
reduced.
[0010] A disadvantage is that the whole arrangement is complex.
Moreover, there is a considerable risk of leakage as a result of
the many connections that have to be made. The installation cost is
also quite high.
[0011] The US 2003/0188542 describes a device in which part of the
compressed air is tapped off after a medium pressure stage of a
compressor, and is then carried to the regeneration zone of an
adsorption dryer, after which the absorbed water in this part of
the compressed air is removed by cooling, and the remaining air is
compressed again with the main flow of the compressed air before
the main flow goes through the drying zone of the adsorption dryer
and leaves the device as dry compressed air.
[0012] A disadvantage of such a device is that the compressed gas
after the medium pressure stage has a much lower temperature than
the compressed gas after the low pressure stage, such that the
tapped-off part of the gas can absorb the water less well from the
adsorption medium, and the adsorption medium cannot dry
quickly.
[0013] To recuperate the heat that is generated upon the
compression of the gas, a heat exchanger is needed for which a tube
heat exchanger is frequently used.
[0014] Tube heat exchangers are already known that consist of a
housing in which one or more tubes extend in the longitudinal
direction between a first inlet and outlet part for a primary
fluid, and a second inlet and outlet part for a secondary fluid,
whereby the primary fluid flows around the tubes and the secondary
fluid flows through the tubes, whereby heat is transferred between
the two fluids.
[0015] In the known heat exchangers the space in the housing
between the second inlet and outlet part can have baffles that
guide the flow of the primary fluid in a zigzag pattern, for
example.
[0016] In so doing the primary fluid cannot flow directly from the
second inlet part to the second outlet part and the heat transfer
is improved.
[0017] The purpose of the present invention is to provide a
solution to one or more of the aforementioned disadvantages and/or
other disadvantages, by providing a device for compressing and
drying gas, and this device contains a multistage compressor with a
low pressure stage, a high pressure stage and a pressure pipe and
an adsorption dryer with a drying zone and a regeneration zone,
whereby an intercooler is placed between this low pressure stage
and high pressure stage, and whereby the device is further provided
with a heat exchanger that is connected to an inlet part by the
aforementioned pressure pipe, and whereby the aforementioned heat
exchanger contains a housing with a number of compartments,
including a main compartment with an aforementioned inlet part and
outlet part for a first primary fluid that is guided in this main
compartment over or around tubes that extend through the main
compartment; whereby there are at least two series of tubes that
extend through the aforementioned main compartment, and which are
each intended for guiding a secondary or tertiary fluid through the
main compartment to exchange heat with the primary fluid; and
whereby a first aforementioned series of tubes forms a cooling
circuit of the aforementioned intercooler in order to heat up gas
from the high pressure stage for the regeneration of the adsorption
dryer.
[0018] An advantage is that the device is very simple to
manufacture.
[0019] In the simplest embodiment of the heat exchanger of the
device, the main compartment is closed off along one side by an end
plate, whereby there is also a cover along the aforementioned side
of the main compartment to form a side compartment between the
cover and the end plate, whereby this side compartment contains the
inlet and outlet compartments for the secondary and tertiary fluid
and whereby U-shaped tubes are fastened to the end plate.
[0020] In another more preferable embodiment, the main compartment
is bounded along two sides by an end plate, and on either side of
the main compartment there is a cover to form two side compartments
between each respective end plate and the cover opposite it.
[0021] An advantage is that fewer connections have to be made, such
that the risk of leaks as a result of an imperfect connection is
kept to a minimum.
[0022] Another advantage is that the installation cost of this
device is rather low. The application of the heat exchanger
according to the invention in this device thereby results in a more
efficient method for compressing and drying gas, which of course
favourably influences the cost of the gas supplied.
[0023] It is after all clear that the application in such a device
for compressing and drying gas enables the functionalities of two
heat exchangers to be integrated into one single heat exchanger,
which of course saves material costs.
[0024] In the most practical embodiment the compressor is
constructed as a multistage compressor with a low and high pressure
stage, whereby there is an intercooler between this low and high
pressure stage, whereby the inlet part of the heat exchanger is
connected to the aforementioned pressure pipe of the compressor,
and whereby a first aforementioned series of tubes form the cooling
circuit of the aforementioned intercooler in order to heat up gas
coming from the high pressure stage for the regeneration of the
adsorption dryer.
[0025] An advantage is that a very energy-efficient device is
realised, as the heat from the compressed gas can be recovered to
heat up part of the gas originating from the high pressure stage,
whereby the aforementioned gas fraction reaches a high temperature,
and in so doing is suitable for use as a regeneration gas for the
adsorption dryer.
[0026] An additional advantage is that, as a result of the
integration of two heat exchangers into a single heat exchanger,
the volume of the composite heat exchanger can be kept
significantly smaller than the combined volumes of two separate
heat exchangers, such that a substantial space saving can be
realised.
[0027] A further additional advantage is that the application of
the heat exchanger is not only limited to devices for compressing
and drying gas, but the heat exchanger can also be used in
applications without an adsorption dryer, subject to a few minor
modifications.
[0028] With the intention of better showing the characteristics of
the invention, a preferred embodiment of a device according to the
invention is described hereinafter by way of an example without any
limiting nature, with reference to the accompanying drawings,
wherein:
[0029] FIG. 1 schematically shows a cross-section of a first
embodiment of a heat exchanger for the device;
[0030] FIG. 2 shows an alternative embodiment of FIG. 1;
[0031] FIG. 3 shows an example of a device for compressing and
drying gas according to the invention;
[0032] FIG. 4 shows an alternative embodiment of FIG. 2.
[0033] FIG. 1 schematically shows a first embodiment of a tube heat
exchanger 1 for a device according to the invention, that primarily
comprises a closed housing 2 with a shell 3, which in this case,
but not necessarily, is cylindrical.
[0034] The housing 2 is closed on both sides by means of a cover 4,
whereby the cover 4 is fastened to the cylinder shell 3, for
example by means of bolts not shown in the drawings that can be
screwed into threaded holes 5B in the shell 3 through passages 5A
in the cover.
[0035] In this embodiment the housing 2 has an end plate 6 that
forms the separation between a main compartment 7 and a side
compartment 8, whereby the main compartment 7 is bounded by the
shell 3 and the cover 4, and whereby the side compartment 8 is
bounded by the end plate 6 and the cover 4 located on this
side.
[0036] In the cylinder shell 3 there is an inlet part 9 and an
outlet part 10 for guiding a primary fluid through the main
compartment 7.
[0037] In the embodiment shown, the aforementioned inlet part 9 and
outlet part 10 are situated on the same side of the shell 3, but
they can of course also be put at other places in the shell 3.
[0038] In the heat exchanger 1 at least two series of tubes 11-12
extend through the main compartment 7, whereby the aforementioned
series 11-12 are each intended for guiding a secondary or tertiary
fluid through the main compartment 7, in order to exchange heat
with the primary fluid that flows over or around that tubes 13 in
the main compartment 7.
[0039] The ends of the tubes 13 of the first series 11 are
connected to a first inlet compartment 14 and a first outlet
compartment 15 for the secondary fluid. Similarly, the ends of the
tubes 13 of the second series 12 are connected to a second inlet
compartment 16 and a second outlet compartment 17 for the tertiary
fluid. According to the invention, the aforementioned inlet and
outlet compartments 14-17 are completely separated from one
another.
[0040] To this end, in the embodiment shown the side compartment 8
is divided by a number of partitions 18 into four sub-compartments
19, respectively the first inlet compartment 14, the first outlet
compartment 15, the second inlet compartment 16, and the second
outlet compartment 17 for the second series of tubes 12.
[0041] In the embodiment shown the tubes 13 are U-shaped, whereby
one side of each tube 13 of the first series 11 opens into the
first inlet compartment 14 and the other side opens into the first
outlet compartment 15. Analogously the tubes 13 of the second
series 12 open into the second inlet and outlet compartments 17-18,
all such that the circuits of the secondary and tertiary fluids are
completely separated from one another.
[0042] In the embodiment of FIG. 1 the main compartment 7 is
equipped with baffles 20 (also called bafflers) whose shape and
relative position are chosen such that a certain pattern of flow is
imposed on the primary fluid, such as a zigzag pattern for example,
such that the primary fluid flows through the main compartment in a
number of passes in a back and forth motion.
[0043] To this end the baffles 20 extend from one side of the main
compartment 7 to a certain distance from the other side of the main
compartment 7, to form reversing passageways 21 for the primary
fluid and this in such a way that the successive reversing
passageways 21 alternate on the one or the other side of the heat
exchanger 1.
[0044] The baffles are preferably made of stainless steel but the
invention is by no means limited to this.
[0045] In another embodiment of the invention, passages are put in
the baffles 20 with a diameter that practically match or which are
slightly larger than the diameter of the tubes 13, whereby there is
a limited margin between the baffles 20 and the tubes 13.
[0046] The presence of the baffles 20 in the heat exchanger 1 is
not necessary.
[0047] FIG. 2 schematically shows a preferred different embodiment
of a tube heat exchanger 1 for a device according to the invention
that primarily comprises a closed housing 2 with a main compartment
7, whereby the main compartment 7 has a first inlet and outlet part
9-10 for a first primary fluid that is guided in the main
compartment 7 over or around the tubes 13 that extend through the
main compartment 7.
[0048] In this embodiment the aforementioned inlet and outlet part
9-10 are located on opposite sides of the shell 3, and which are as
far from one another as possible, as seen from an axial
direction.
[0049] This more or less diagonal arrangement of the inlet and
outlet part enables a more efficient heat transfer.
[0050] It is of course possible for the inlet and outlet part 9-10
for the primary fluid to be on the same side of the shell 3 or at
other places in the shell 3.
[0051] In contrast to the embodiment of FIG. 1, in FIG. 2 the main
compartment 7 is bounded by two end plates 6 and on either side of
the main compartment 7 there is a cover 4 to form two side
compartments 8 between each respective end plate 6 and the cover 4
opposite it.
[0052] In the most practical embodiment of the invention, the tubes
13 that extend through the main compartment 7 are fastened on one
of the two end plates 6A, whereby this end plate 6A is clamped
between the housing 2 and the cover 4A located opposite this end
plate 6A.
[0053] The tubes 13 are thereby secured in a gas tight manner in
the passages of the end plates 6, for example by soldering or
similar.
[0054] Preferably the end plates 6 are different to one another and
one of the two end plates 6B has smaller dimensions, which enables
this end plate 6B to be arranged in a floating manner, all such
that the thermal expansion is accommodated.
[0055] In the cross-section of FIG. 2, the end plate 6A to which
the tubes 13 are secured has larger dimensions than the other end
plate 6B, and the smallest end plate 6B is affixed movably in a
ring between the shell 3 and the cover 4B.
[0056] In this embodiment, the side compartments 8 are connected
together on either side of the aforementioned end plates 6 by means
of parallel tubes 13, whereby the aforementioned tubes 13 run
through the main compartment 7 and extend through passages 22 in
these end plates 6.
[0057] Of course baffles can also be provided in this embodiment,
but this is not necessary.
[0058] According to a preferred characteristic of the heat
exchanger, the aforementioned side compartments 8 are subdivided
into two or more sub-compartments 19.
[0059] To this end, in the cross-section shown, on the inside of
the cover there are one or more straight upright walls or
partitions 18 and there is a seal 23 between the edges of these
walls 18 and the end plate 6.
[0060] In the variant according to FIG. 2, in each side compartment
8 there are two sub-compartments 19 for guiding a secondary or
tertiary fluid.
[0061] In the cross-section of FIG. 2, a first sub-compartment 19A
connects to a first series 11 of tubes in the main compartment 7,
and all tubes 13 of the aforementioned series 11 open out into the
same sub-compartment 19B on the other side of heat exchanger 1.
[0062] The sub-compartments 19A and 19B are thereby situated in
line with one another.
[0063] Analogously, the two other sub-compartments 19C-19D can be
connected together by a second series 12 of tubes.
[0064] Preferably the sub-compartments 19 for the secondary and
tertiary fluid are completely separated from one another and each
fluid circulates in its own separate circuit for the fluid
concerned.
[0065] Although it could be derived from the cross-section shown
that the number of tubes 13 of the two series 11-12 must be the
same, arrangements are also possible whereby the number of tubes 13
is different for the secondary and tertiary fluid.
[0066] Of course the diameters of the tubes 13 for the secondary
and tertiary fluid can also differ from one another.
[0067] It is also possible that the tubes 13 for the secondary and
tertiary fluid can also present a different internal form and/or
that a few tubes 13 can be provided with fins or other means in
order to foster the heat transfer between the primary fluid and the
secondary and/or tertiary fluid.
[0068] In the simplest embodiment, the aforementioned first series
of tubes 11 for the secondary fluid is situated in the top half of
the heat exchanger 1 and the tubes of the second series 12 for the
tertiary fluid are in the bottom half.
[0069] At the level of the aforementioned wall 18 and seal 23, a
space 24 is left in the main compartment 7 between the first and
second group of tubes 11-12.
[0070] Of course the heat exchanger is not limited to such
arrangements shown and alternative arrangements are also possible,
such as for example a concentric arrangement in which the tubes of
the first group 11 are located around the axis of the heat
exchanger 1 and whereby the second group of tubes 12 forms a
concentric ring of tubes around the aforementioned first group
11.
[0071] Another possible arrangement is with the tubes of the first
series 11 distributed over a first sector of a circle, and the
tubes of the second series 12 are distributed over another sector
of a circle.
[0072] Of course the two sectors do not necessarily have to be the
same size and together they can form a full circular disk or
otherwise.
[0073] The operation of the heat exchanger 1 for a device according
to the invention is very simple and as follows.
[0074] A primary fluid is guided to the main compartment 7 via the
inlet part 9 in the shell 3, whereby when flowing through the main
compartment 7 this primary fluid is guided by means of any baffles
20 according to a certain pattern, as indicated by the arrows P in
FIG. 1.
[0075] At the same time two fluids, that may or may not be
different, flow through the tubes 13 of the main compartment 7,
i.e. a secondary fluid that flows through the tubes 13 of the first
series 11 in a direction according to the arrow Q, and a tertiary
fluid that flows through the tubes 13 of the second series 12 in a
direction R.
[0076] In the cross-section shown, the directions Q and R of the
secondary and tertiary fluid are opposite one another, but this is
not a strict requirement of the device according to the
invention.
[0077] As a result, in the main compartment 7 heat will be
transferred between the primary fluid and the secondary fluid on
the one part and between the primary fluid and the tertiary fluid
on the other part.
[0078] It goes without saying that the secondary and tertiary fluid
that flows through the tubes 13 can be a gas, gas mixture or
liquid, or that the secondary fluid is a gas and the tertiary fluid
a liquid or similar.
[0079] The heat exchanger 1 is particularly suitable for a device
according to the invention for compressing and drying gas, an
arrangement of which is shown in FIG. 3 by way of an example.
[0080] This device 25 consists of a compressor device 26 and an
adsorption dryer 27 and has an inlet 28 that connects to the
entrance of the compressor device 26, and an outlet 29 that guides
the dried compressed gas to a consumer network not shown in the
drawing.
[0081] The compressor device 26 shown is a multistage compressor
with, in this case, three compressor elements 30-32 connected in
series to form a low pressure stage 30, a medium pressure stage 31
and a high pressure stage 32.
[0082] Each compressor element 30-32 is driven by an electric motor
33, and downstream from each compressor element 30-32 there is a
cooler 34-36, respectively two intercoolers 34-35 and an
after-cooler 36.
[0083] Each of the aforementioned coolers 34-36 cool the gas
compressed by the compressor element 30-32 concerned.
[0084] Preferably, there are liquid-gas coolers in such a device
25, whereby the gas to be cooled is guided through the cooler 34-36
as a primary fluid, and a coolant is guided through the tubes as a
secondary fluid.
[0085] Between the low-pressure stage 30 and the medium pressure
stage 31 there is a heat exchanger 37 upstream from the intercooler
34, which together with the intercooler 34 is integrated into a
heat exchanger 1 in a device according to the invention.
[0086] In FIG. 3 the heat exchanger 1 is schematically shown by a
box around the heat exchanger 37 and the intercooler 34.
[0087] Preferably the heat exchanger 1 has an inlet part 9 for the
compressed gas originating from the low pressure stage 30 and an
outlet part 10 that is connected to the inlet of the medium
pressure stage 31.
[0088] The heat exchanger 37 has an inlet compartment 14 that is
directly connected via a branch pipe 38 to the outlet pipe 39 of
the high pressure stage 32 for tapping off a quantity of compressed
gas along the direction of the arrow Q.
[0089] Furthermore the heat exchanger has an outlet compartment 15
that is connected to the regeneration zone of the adsorption dryer
27.
[0090] The intercooler 34 has an inlet compartment 16 and outlet
compartment 17 that act as an inlet and outlet for an external
cooling circuit, for example a flow of water that flows through
this intercooler 34 in the direction of the arrows R.
[0091] In the arrangement shown the entire flow of the gas, that is
compressed by the low pressure stage 30, flows through the heat
exchanger 37 and through the intercooler 34 and this in the
direction of the arrows P.
[0092] The adsorption dryer 27 is for example of the type with a
rotating drum with regeneration zone 40 and a drying zone 41 that
is filled with a desiccant, whereby the desiccant is sent
alternately through this drying zone 41 and regeneration zone 40 by
means of a motor.
[0093] After cooling in the after-cooler 36, the compressed gas
from the high pressure stage 32 is guided through the drying zone
41 via an ejector 42, and after drying is sent to a consumer
network via the outlet 29.
[0094] The gas that leaves the heat exchanger 37 via the outlet
compartment 15 is linked back to the dryer 27 and guided through
the regeneration zone 40 to then be combined, via a cooler 43 and
via the aforementioned ejector 42, with the gas that is sent
through the drying zone 41.
[0095] It is clear that a combined heat exchanger for a device
according to the invention constitutes a dual function and acts as
a first heat exchanger that fulfils the role of intercooler 34,
whereby an external cooling fluid is used, and a second heat
exchanger 37, whereby a tapped-off part of hot gas from the high
pressure stage 32 is first additionally heated by bringing this gas
into contact with the gas from the low pressure stage 30, whose
temperature in the arrangement shown is higher than that of the
compressed gas of the high pressure stage 32.
[0096] In this way a more efficient operation of the adsorption
dryer 27 is obtained.
[0097] It is clear that in the device shown, the compression heat
of the first low pressure stage 30 is recuperated, in contrast to
the better known simpler devices where this heat is lost with the
coolant that flows through the first intercooler 34.
[0098] In addition such a device is extra beneficial because an
external heating element is not required to heat up the
regeneration gas and because the intercooler 34 can be kept
smaller.
[0099] FIG. 4 shows another possible variant of a heat exchanger
for a device according to the invention that is different to the
one of FIG. 2 in that the inlet compartment 16 and outlet
compartment 17 for the tertiary fluid are situated in the same
cover 4.
[0100] To this end, one of the two side compartments 8 has an extra
wall so that the inlet and outlet compartment 16-17 for the
tertiary fluid are completely separated from one another.
[0101] In the cross-section shown, the tertiary fluid of the inlet
compartment 16 flows through the bottom series 12 of tubes to the
outlet compartment 17 via the top series 12 of tubes via the
compartment 44.
[0102] Although in FIG. 4 there are no baffles 20 in the main
compartment 7, variants with baffles 20 are possible so that the
primary fluid flows through the main compartment 7 in a number of
passes in a back and forth motion.
[0103] It will be clear to a man skilled in the art that many other
variants are also possible, whereby for example a cover 4 contains
the inlet compartment 14 and outlet compartment 15 of the secondary
fluid and the other cover 4 contains the inlet compartment 16 and
outlet compartment 17 of the tertiary fluid.
[0104] It is also not excluded to provide two inlet compartments
14-16 and two outlet compartments 15-17 in a single cover so that
the other cover can be constructed without inlet or outlet
compartments.
[0105] It will be clear to a man skilled in the art that there are
many possibilities for the choice of the position and size of the
different sub-compartments, and that certain arrangements could be
more beneficial for example, depending on the practical
application.
[0106] The present invention is by no means limited to the
embodiment described as an example and shown in the drawings, but a
device according to the invention can be realised in all kinds of
variants, without departing from the scope of the invention.
* * * * *